This project was designed to allow NIH scientists to easily and accurately quantitate one- and two-dimensional gels. Quantitative comparisons of two gels is semi-automatic, and one project has used methods developed here to separate the results of double-labeled radiography of protein gels using color negative film and appropriate filters. This is possible because tritium and spillover of carbon 14 are recorded in the blue sensitive layer of the film while carbon 14 alone is recorded in the green or red sensitive layer. This method was used to analyze the effect of growth rate and medium composition on the relative levels of individual proteins in a pathogenic strain of Escherichia coli.